基于阻尼特性的发动机液压链条张紧器参数优化

为提高链条液压张紧器在振动过程中的阻尼性能,在对张紧器动力学分析的基础上,使用AVLExcite—TD软件建立其仿真模型．以阻尼能为评价指标对其关键参数进行正交试验,通过对试验结果极差、方差分析张紧器参数对阻尼性能的影响,实现其全面优化,参数优化后阻尼能提高59．70％．在25～200Hz激励频率下．阻尼能为3．2731～5．1337J,在各频率下均具有良好的阻尼性能．     

基于虚拟样机技术的含间隙转动铰建模方法

对基于ADAMS的含间隙转动铰虚拟样机建模方法进行研究．利用无质量圆弧间的接触约束建立等效含间隙转动铰,采用Hertz弹性接触理论建立碰撞力模型,采用三次多项式近似的阶跃函数建立粘性阻尼模型,采用基于速度的阶跃函数建立摩擦力模型．通过一合多间隙转动铰曲柄摇杆机构的动力学仿真算例,分析不同连接处的含间隙转动铰元素之间的相对运动关系,并对三类常见运动副间隙模型的适用性进行了讨论．结果显示利用ADAMS进行动力学仿真是研究含多间隙转动铰机构的一种有效方法．     

船用吊机机械防摆系统建模与实验研究

为解决船舶起重机受到外部激励造成吊重较大摆动的问题,通过建立三绳位置跟随防摆模型和三绳阻尼式张力防摆模型的方法研究了一种三绳防摆机理。结果表明:进行三绳张力防摆控制时,吊重防摆效果可达53.8%。由此可见,该防摆方案准确合理,能够提高吊机的工作效率和吊装安全。     

基于MATLAB／SIMULINK的电力电子实验仿真

电力电子技术是一门实践性很强的专业基础课,为加深理论知识,加强该门课程的实验教学效果,本文提出了一种基于MATLAB／SIMULINK实验的设计思想,开发出相应的仿真平台,并建立了三相半波可控整流电路的动态仿真模型,给出了仿真实例并验证了模型的正确性,从而为电力电子实验教学提供了一个有效的辅助工具．     

非理想反激变换器连续工作模式建模分析

基于电路平均法,同时考虑实际变压器、二极管、电容、MOSFET管寄生参数的影响,在连续工作模式下建立非理想反激变换器直流和小信号模型,并推导出传递函数．模型分析以及仿真结果证实所建模型能够准确地反映变换器的实际特性．     

速率方位平台惯性导航系统研究

为了降低重力无源导航系统成本,在速率方位平台上放置一个重力敏感器,以构成集重力仪和导航仪为一体的系统.根据该系统的特点对速率方位平台惯性导航系统进行了研究,给出了该系统的导航计算公式、速率方位平台姿态角、系统速度和位置的误差方程以及加速度计和陀螺仪的随机误差模型.用MATLAB/Simulink工具对无阻尼和有阻尼速率方位平台惯性导航系统进行了计算机仿真,仿真结果表明带阻尼的速率方位平台惯性导航系统平台误差角和定位误差小,能够满足重力测量和导航要求.     

有阻尼受迫振动系统的计算机仿真分析

介绍了一种基于MATLAB/Simulink环境下有阻尼受迫振动系统的仿真分析方法.它是根据系统的数学模型建立Simulink仿真模型,利用软件强大的仿真功能生成可视化的图形.在物理学和控制理论等课程中,恰当运用该技术来仿真,可加深对复杂振动系统的理解.     

有关实用新型专利授权之后的检索报告

本文通过分析目前实用新型检索报告中存在的不足,参考国外一些国家的做法并结合自己的审查实践,提出了一些建议。为了对实用新型专利授权之后专利有效性的评判作进一步的完善,笔者建议将目前的实用新型“初步审查”+“授权后的检索报告”改为“初步审查”+“授权后的实质审查”为好。     

论完善我国专利侵权损害赔偿制度

我国专利侵权损害赔偿制度中存在着赔偿范围不明确、计算赔偿金 额的标准和方法不完善、没有建立起完善的惩罚性赔偿制度以及现 行诉讼程序使专利权人合法权益得不到及时有效保护等缺陷。笔者 提出应明确赔偿范围,完善赔偿金的标准和计算方法,建立惩罚性 赔偿制度,建立法定赔偿金制度,对实用新型和外观设计专利实行 诉前审查制度等立法建议。     

磁记录浮动系统频谱仿真

建立了考虑气膜刚度、阻尼分布特征与非线性性质的浮动系统动态特性综合分析的近似模型；给出了浮动系统固有频率及其变化特性的仿真测试方法与结果。     

磁流变液阻尼器设计与性能测试

自动化生产中,自动检测设备的使用越来越广泛,为保证检测精度,这类设备都需要控制气动和电动振动对检测的干扰和影响．为此本文设计了MRF可控阻尼器及可调振动滑台装置,总结基于MRF力学模型和磁路设计模型,设计MRF阻尼器的经验;基于NI数字化测试系统检测MRF阻尼器控制移动滑台振动的效果．实验结果证实MRF阻尼器能快捷方便地调节阻尼、高精度控制移动滑台的振动,MRF阻尼器振动控制装置具有教学实用价值．     

Experimental Studies on High-Frequency Performance of the Inverse Control Magneto-Rheological Damper

Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological(MR) damper was designed to control the vibration. The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the parameters of the model keep stable in the ranqe of 15-50 Hz.     

基于有限元分析模型建立的轿车车门动态特性分析

轿车车门是轿车车身重要的组成部分,它的设计质量直接影响整车的安全性、造型效果、空气动力学特性、密封性及噪声等。轿车车门动态特性分析是基于车门有限元分析模型的建立,对轿车车门在自由状态下进行模态分析。文章在四种工况下对轿车车门的扭转刚度、下垂刚度进行分析。通过分析,为轿车车门结构设计选择及结构优化提供了理论依据。     

由MR阻尼器驱动的汽车悬架减振系统的半主动控制研究

设计了一种半主动力跟踪PI控制器，对由磁流液(MR)阻尼器作为悬架阻尼器的汽车模型进行控制分析．MR阻尼器的2种不同模型在闭环的汽车悬架控制系统模型中得到了应用．2种模型是基于均值阻尼力对速度(f-v)特性的均值F-v模型，和描述阻尼力非光滑滞环和饱和特性的滞环f-v模型．汽车模型用来研究力跟踪PI控制算法和MR阻尼器对车辆的振动抑制性能．仿真分析还指出了MR阻尼器的非线性，特别是滞环特性对汽车悬架系统的性能影响．结果表明所提出的控制方法对由MR阻尼器驱动的汽车悬架系统能产生很好的减振效果，不仅体现在对悬架弹簧支撑车厢的共振抑制和对驾乘人员舒适性敏感频域的振动抑制，还体现在对汽车轮胎共振频率周围的振动抑制．结果还进一步说明了MR阻尼器所存在的滞环特性对汽车悬架性能的不良影响．     

A new controller for the semi-active suspension system with magnetorheological dampers

~~under the sliding mode controller. It shows that the sliding mode controller yield almost perfect tracking to the reference model. It can be seen in Fig.6 that the acceleration of sprung mass under sliding mode controller is controlled within ?.7 m/s2. Fig.7 shows the robustness and stability of the sliding mode controller to the parameter variations of the system to be controlled, in this case, a relative decrease of 10 % in the sprung mass and a relative increase of 15 % in the stiffness o…     

Seismic response analysis of damper-connected adjacent structures with stochastic parameters

Dynamic response analysis of damper connected adjacent multi-story structures with uncertain parameters is carried out. A formula of the multi degree of freedom （MDOF） for the structure-damper system with stochastic parameters is derived. The uncertainties of mass and stiffness are taken into consideration firstly. The ground acceleration is represented by Kanai-Tajimi filtered non-stationary process. The mean square random responses of structural displacement and story drift are chosen as the optimization objective. The variations of mean square responses of top floor displacements and bottom story drifts in neighboring structures with the damper stiffness and damping coefficient are analyzed in detail. Through the parametric study, the acquiring optimum parameters of damper are regarded as numerical results. Then, a reducing order model of the MDOF system for adjacent structures with mean parameters is presented. The explicit expressions for determining optimal parameters of Kelvin model-defined damper which is used to connect adjacent single degree of freedom （SDOF） structures subjected to a white-noise excitation are employed to achieve the appropriate damper parameters, which are called theory results. Through a comparative study, it can be found that the theory values of damper parameters are consistent with the results based on extensive parametric studies. The analytical results can be obtained by using the first natural frequencies and the total mass of the adjacent deterministic structures with mean parameters. The analytical formulas can be used to find appropriate parameters of damper between adjacent structures for engineering applications. The performance of damper is investigated on the basis of mitigations of mean square random responses of inter-story drifts, displacements and accelerations in adjacent structures. The numerical results demonstrate the robustness of coupled building control strategies.     

A new controller for the seni-active suspension system with magnetor heological dampers

A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances.     

橡胶浮置板轨道对城市高架箱梁减振特性数值分析

为了研究橡胶浮置板轨道对城市高架箱梁结构的减振特性,建立了高架橡胶浮置板轨道结构三雏有限元模型,分析了当减振器刚度和轨道板长度变化对高架桥系统动力响应影响。研究结果表明。减振器刚度的改变对浮置板前10阶振动频率分布影响较大,对累积质量分数分布特性几乎没有影响,相同阶数条件下浮置板的振动主频随减振器刚度减小而减小;列车通过时浮置板轨道以增大自身的振动来达到减小对桥梁结构振动能量输入的目的,在减振频率范围内,浮置板的减振效果随减振器刚度增大而减小,随浮置板长度的减小而减小。     

Experimental Study on Magnetorheological Damper for Semi-Active Vibration Control of Civil Infrastructures

Magnetorheological (MR) fluid is a kind of smart material whose rheological properties can be rapidly varied in magnetic field. To make full use of the advantages of MR fluid to devices, a model of double-ended,shear-combined and valve-typed MR damper is designed and manufactured, and the dynamic properties under sinusoidal excitations are experimentally studied. The experiment results show that the maximum damping force of the MR damper at the full magnetic intensity reaches about 20 k while the maximum power required is less than 50W, which predicts that the MR damper will be a powerful measurement for semi-active vibration control of civil infrastructures.     

A disc-type magneto-rheologic fluid damper

A disc-type magneto-rheological fluid damper operating in shear mode is proposed in this paper, which is based on the special characteristics of the magneto-rheological (MR) fluid with rapid, reversible and dramatic change in its rheological properties by the application of an external magnetic field. The magnetic field of the disc-type MR fluid damper is analysed by the finite element method; the controllability of the disc-type MR fluid damper on the dynamic behaviour of a rotor system; and the effectiveness of the disc-type MR fluid damper in controlling the vibration of a rotor system, are studied in a flexible rotor system with an over-hung disc. It is shown that the magnetic flux density of the disc-type MR fluid damper in the working areas can significantly change with the applied current in the coil; and that the dynamic behavior of the disc-type MR fluid damper can be varied by the application of an external magnetic field produced by a low voltage electromagnetic coil. The disc-type MR fluid damper can significantly change the dynamic characteristics of a rotor system, provided that the location of the disk-type MR fluid damper is carefully chosen. The disc-type MR fluid damper is a new actuator with good dynamic characteristics for rotating machinery.